VMware clients does not list in Host properties of Master server, and they does not need to have Netbackup clients installed for backups... they need to netbackup installed and configured only in case you are looking for file and direcotry restore in the the VM.
if you would like to have the list of VMs,
1) if you are using the manual vm seleciton you can pull that info form Clients tab from VM.
2) if you are using query based Vm selection in policy.. you need to run test query from policy or nbdiscover command to get the VMs that are included in Backups..( this list is dynamic)